Biaxial stretch blow molding machine

ABSTRACT

A biaxially stretching blow molding apparatus perform biaxial stretch-molding for a preform into a predetermined shape by transporting a preform carrier supporting the preform along a transporting path extending across a heating portion and a stretch-molding portion, has first and second reversing means for reversing the preform carrier, and first and second transporting paths forming the transporting path. The first reversing means receives the preform carrier transported in up-side-down position along the second transporting path, reverses the received preform carrier into elected position, and transfers the preform carrier thus reversed to the first transporting path. The second reversing means receives the preform carrier transported in elected position along the first transporting path, reverses the received preform carrier into the up-side-down position, and transfers the preform carrier thus reversed to the second transporting path.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a biaxially blow molding apparatusforming a predetermined shape of molded product by transporting apreform carrier carrying a preform along a transporting path extendingacross a heating portion and a stretch-molding portion and by performingbiaxially stretching blow molding for the preform.

2. Description of the Related Art

A biaxially stretching blow molding apparatus producing resin products,such as PET bottle or so forth, by biaxially stretching blow molding, isconstructed to heat a primary molded product which is called as apreform, up to a temperature adapted for molding during transportationacross the heating portion, and then perform biaxially stretching blowmolding for the preform in a stretch-molding die forming thestretch-molding portion.

A typical biaxially stretching blow molding apparatus has a constructionincluding a preform supply portion, a preform heating portion, astretch-molding portion and a molded product taking out portion, andcontinuously or intermittently circulating a plurality of preforms alonga guide rail defining a transporting path extending across respective ofthe foregoing portions. On the other hand, a typical preform carrier hasa construction including a slide portion guided by the guide rail tomove therealong, and a core portion extending from the slide portion tobe inserted into the preform.

The preform is loaded on each preform carrier in the preform supplyportion so that an opening mouth of the preform is set on the coreportion of the preform carrier. On the other hand, the molded productobtained by performing biaxially stretching blow molding for the preformin the stretch-molding portion is unloaded from each preform carrier byreleasing an opening in a neck portion of the molded product from thecore portion of the preform carrier in the product taking out portionand collected in a predetermined collecting site. Furthermore, the emptypreform carrier unloaded the molded product is returned to the preformsupply portion for loading the next preform.

In the biaxially stretching blow molding apparatus having a constructionto support the preform by the preform carrier which is continuouslytransported along the predetermined circulating path, it has beenstrongly demanded to speeding up operation at respective portions forimproving overall process performance and whereby for improving costeffectiveness.

On the other hand, the preform carrier unloaded the molded product afterpassing through the stretch-molding portion is schematically returned tothe preform supply portion again by-passing the stretch molding portion.When the by-pass passage for the empty preform carrier can be formedthrough a dead space below the stretch-molding portion, the circulatingpath may be constructed in compact. In such case, height difference iscaused in the circulating path to require transfer of the preform, themolded product and the preform carrier between the transporting pathshaving height difference. If transfer operation can be done efficiently,process speed of the biaxially stretching blow molding apparatus can beimproved.

Next, the preform transported by the preform carrier along thecirculating path is formed into the molded product which has greaterwidth and greater height in comparison with the preform in thestretch-molding portion. Therefore, it becomes necessary to providegreater feeding pitch of the preform carrier on the upstream side of thestretch-molding portion. If transporting operation for the preformcarrier can be done efficiently by converting operation of the feedingpitch and with widened feeding pitch, process speed of the biaxiallystretching blow molding apparatus can be further improved.

On the other hand, a mold clamping mechanism which opens and closes apair of stretch-molding dies in order to perform stretch-molding of thepreform, generally has a construction to open and close eachstretch-molding dies which are slidably supported, by means of an aircylinder via a toggle link mechanism. If opening and closing operationof the stretch-molding dies by the mold clamping mechanism can be doneefficiently, process speed of the biaxially stretching blow moldingapparatus can be further improved.

SUMMARY OF THE INVENTION

The present invention has been worked out in order to satisfy demandsset forth above. Therefore, it is an object of the present invention toprovide a biaxially stretching blow molding apparatus which has highprocess speed by improving efficiency of operation in respectivecomponents.

Another and more particular object of the present invention to provide abiaxially stretching blow molding apparatus which can efficientlyperform transfer operation of a preform, a molded product and a preformcarrier between transporting paths having height difference.

A further object of the present invention is to provide a biaxiallystretching blow molding apparatus which can efficiently perform anoperation for expanding a feeding pitch of the preform carriers onupstream side of a stretch-molding portion and a transporting operationof the preform carrier with the expanded feeding pitch.

A still further object of the present invention is to provide abiaxially stretching blow molding apparatus which can efficientlyperform mold clamping operation of a pair of stretch-molding dies forperforming biaxially stretching blow molding.

In order to accomplish the above-identified and other objects, accordingto the first aspect of the present invention, a biaxially stretchingblow molding apparatus perform biaxial stretch-molding for a preforminto a predetermined shape by transporting a preform carrier supportingthe preform along a transporting path extending across a heating portionand a stretch-molding portion, comprises:

first and second reversing means for reversing the preform carrier;

first and second transporting paths forming the transporting path;

the first reversing means receiving the preform carrier transported inup-side-down position along the second transporting path, reversing thereceived preform carrier into elected position, and transferring thepreform carrier thus reversed to the first transporting path; and

the second reversing means receiving the preform carrier transported inelected position along the first transporting path, reversing thereceived preform carrier into the up-side-down position, andtransferring the preform carrier thus reversed to the secondtransporting path.

In order to make the first and second transporting paths compact, it ispreferred that the first transporting path is an upper transporting pathextending across a stretch-molding position of the stretch-moldingportion, and the second transporting path is a lower transporting pathextending lower side of the stretch-molding portion. With thisconstruction, in comparison with the case where the second transportingpath is arranged by-passing the stretch molding portion having largestdimension in the width direction in lateral direction, the biaxiallystretching blow molding apparatus can have compact construction.

On the other hand, it is possible that at least one of the first andsecond reversing means has a pivoting member pivoting about apredetermined pivot center and a pair of preform holding portion formedat symmetric positions of the pivoting member with respect to the pivotcenter. In this case, it is desirable that one of the preform holdingportions being placed at a height corresponding to the uppertransporting path and the other preform holding portion being placed ata height corresponding to the lower transporting path at pivot stopposition of the pivoting member.

With the construction set forth above, whenever the pivoting member ispivoted, both of the preform carrier holding portions are respectivelypositioned at the height positions corresponding to the upper and lowertransporting paths. Therefore, transfer of the preform carriers betweenrespective preform carrier holding portions and the upper and lowertransporting paths can be done efficiently.

Here, the preform holding portion may have a guide groove, into whichthe preform carrier can be inserted in lateral direction in a conditionnot withdrawn in vertical direction. On the other hand, the preformcarrier may have a slide portion sliding along the transporting path andbeing inserted into the guide groove, and a core projecting from theslide portion for inserting into the preform.

The biaxially stretching blow molding apparatus may further comprise apreform supply portion. The preform supply portion may comprise:

the first reversing means having the pivoting member and the preformcarrier holding portion;

preform inserting means for loading an opening portion of the preformfrom lower side to the core of the preform carrier held in up-side downposition in a guide groove of one of the preform carrier holdingportions in the first reversing means; and

feeding out means for feeding out the preform carrier held in electedposition with supporting the preform in the guide groove of the otherpreform carrier holding portion of the first reversing means.

With the preform supply portion constructed as set forth above, whileoperation for receiving the empty preform carrier in one of the preformcarrier holding portions, preform loading operation for the preformcarriers and transferring of the preform carriers supporting thepreforms to the transporting path are performed on the side of the otherpreform carrier holding portion. Since mutually different operations areperformed simultaneously in both of the preform carrier holdingportions, operation of the preform supply portion can be efficient toenhance process speed of the biaxially stretching blow moldingapparatus.

Here, it is desirable that the preform supply portion has a droppreventing means for preventing dropping of the preform loaded on thecore of the preform carrier by the preform inserting means from thecore.

On the other hand, by arranging the preform carrier holding portions atsymmetric positions relative to the reversing shaft as a center of thepivoting member, complete balance in weight can be established tocontribute for speeding up reversing operation.

Next, the biaxially stretching blow molding apparatus has a moldedproduct taking out portion. The molded product taking out portion maycomprises:

the second reversing means having the pivoting member and the preformcarrier holding portion;

a pair of gripping pieces gripping neck portions of the molded productsfrom both sides loaded on the preform carriers respectively held in thepreform carrier holding portion;

gripping piece opening and closing means for moving the gripping piecesbetween a molded product gripping position and a molded productreleasing position;

molding product removing means for removing the core of the preformcarrier from the neck portion of the molded product gripped by thegripping pieces;

a pair of guide plates which can be guided in a horizontal directionwith supporting the neck portions of the molded products loaded on thepreform carriers respectively held in the preform carrier holdingportion;

guide plate opening and closing means for moving the guide platesbetween a guiding position of the molded product and a molded productreleasing position retracted from the guiding position.

In the molded product taking out portion constructed as set forth above,while operation for receiving the preform carrier supporting the moldedproduct in one of the preform carrier holding portion, withdrawal of themolded products from the preform carriers and feeding out of the emptiedpreform carriers are performed in the other preform carrier holdingportions. Since mutually different operations are performedsimultaneously in both of the preform carrier holding portions,operation of the molded product taking out portion can be efficient toenhance process speed of the biaxially stretching blow moldingapparatus.

Herein, it is desirable that the molded product taking out portioncomprises detecting means for checking good item and no-good item of themolded product supported by the preform carrier; and control means forcontrolling opening and closing of a pair of the pair of gripping piecesand the pair of guide plates on the basis of result of checking by thedetecting means and controlling opening and closing of a pair of thepair of gripping pieces and the pair of guide plates when the preform issupported without being blow molded.

On the other hand, similarly to the preform supply portion, by arrangingthe preform carrier holding portions at symmetric positions relative tothe reversing shaft as a center of the pivoting member, complete balancein weight can be established to contribute for speeding up reversingoperation.

According to the second aspect of the present invention, a biaxiallystretching blow molding apparatus perform biaxial stretch-molding for apreform into a predetermined shape by transporting a preform carriersupporting the preform along a transporting path extending across aheating portion and a stretch-molding portion, comprises:

a pitch expansion mechanism for expanding a feed pitch of the preformcarriers fed into the stretch-molding portion and feeding out from thestretch-molding portion,

a transferring mechanism for feeding said preform carrier into saidstretch-molding portion and for feeding out said preform carrier fromsaid stretch-molding portion by said pitch expansion mechanism.

the pitch expansion mechanism including first and second holding memberssimultaneously holding at least first and second preform carrierstransported along the transporting path in lateral direction, holdingmember moving means for expanding an interval between the first andsecond holding members, in which the preform carriers are held, andholding member moving means for moving the first and second holdingmembers between a preform holding position and a retracted positionretracted from the preform holding position, and

the transferring mechanism including a holding plate holding the firstand second preform carriers from lateral direction after expanding thepitch, holding plate moving means for moving the holding plate between apreform holding position and a retracted position retracted from thepreform holding position, and holding plate feeding means for moving theholding plate along the transporting path for feeding the first andsecond preform carriers which is expanded the pitch therebetween intothe stretch-molding portion and feeding out from the stretch-moldingportion.

In the biaxially stretching blow molding apparatus constructed as setforth above, pitch expanding operation and transporting operation of thepreform carrier with the expanded pitch are performed separately andindependently of the other. Accordingly, in comparison with the casewhere both operation are performed with the single mechanism to performthese operation more quickly to result in higher process speed of thebiaxially stretching blow molding apparatus.

According to the third aspect of the present invention, a biaxiallystretching blow molding apparatus perform biaxial stretch-molding for apreform into a predetermined shape by transporting a preform carriersupporting the preform along a transporting path extending across aheating portion and a stretch-molding portion, comprises:

the stretch-molding portion having a pair of stretch-molding dies and aclaming mechanism for opening and closing the stretch-molding dies;

the clamping mechanism comprising:

a first toggle link mechanism for moving one of the stretch-molding diesbetween an opening position and a closing position;

a second toggle link mechanism for moving the other the stretch moldingdie between an opening position and a closing position; and

a swing mechanism for reciprocally moving the first and second togglelink mechanism at respective link connection points in oppositedirection in synchronism with each other.

The swing mechanism comprises swing member, first and second endportions of the swing member located at symmetric position about swingcenter, and first and second connecting members connected to respectivelink connection points of the first and second toggle link mechanisms.

With the clamping mechanism constructed as set forth above, since dieopening operation and clamping operation of a pair of stretch-moldingdies can be performed with complete synchronization with the other,these operation can be done efficiently. On the other hand, the firstand second toggle link mechanism are moved in mutually oppositedirections. Also, load to be exerted upon clamping and opening of diescan act symmetrically about the center of swing motion, localconcentration of the load upon clamping or die opening may not act.Furthermore, no impact force may be exerted. Accordingly, theseoperation can be done smoothly. Thus, since clamping and die opening canbe done smoothly, clamping operation and die opening operation can bedone quickly and smoothly to result in higher process speed of thebiaxially stretching blow molding apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood more fully from the detaileddescription given herebelow and from the accompanying drawings of thepreferred embodiment of the present invention, which, however, shouldnot be taken to be limitative to the invention, but are for explanationand understanding only.

In the drawings:

FIG. 1A is a schematic plan view of a biaxially stretching blow moldingapparatus, to which the present invention is applied;

FIG. 1B is a schematic side elevation of the biaxially stretching blowmolding apparatus of FIG. 1A;

FIG. 2A is an explanatory illustration showing a shape of a preform;

FIG. 2B is an explanatory illustration showing a structure of a preformcarrier;

FIG. 2C is an explanatory illustration showing a shape of a moldedproduct;

FIGS. 3A and 3B are schematic sections of an upper transporting path anda lower transporting path in the biaxially stretching blow moldingapparatus of FIGS. 1A and 1B;

FIG. 4 is a schematic constructional illustration of a preform supplyportion in the biaxially stretching blow molding apparatus of FIG. 1 asviewed from a preform transporting direction;

FIG. 5 is a schematic constructional illustration showing the preformsupply portion of FIG. 4 as viewed from a direction perpendicular to thepreform transporting direction;

FIG. 6 is a schematic constructional plan view of the preform supplyportion of FIG. 4;

FIG. 7 is a schematic constructional illustration of the case where thepreform supply portion is viewed in a direction of arrow A of FIG. 6;

FIG. 8 is a schematic constructional illustration of the case where apitch expansion mechanism and a transfer mechanism are viewed from apreform transporting direction in the biaxially stretching blow moldingapparatus of FIG. 1;

FIG. 9 is a schematic plan view of the pitch expansion mechanism of FIG.8;

FIG. 10 is a schematic plan view of the pitch expansion mechanism ofFIG. 8;

FIG. 11A is schematic plan view of a transfer mechanism on FIG. 8;

FIG. 11B is an explanatory illustration showing a motion path of atransfer member;

FIG. 12 is a schematic partial constructional illustration of astretch-molding portion in the biaxially stretching blow moldingapparatus of FIG. 1;

FIG. 13 is a schematic constructional illustration of a clampingmechanism of the biaxially stretching blow molding apparatus of FIG. 1as viewed from a preform transporting direction;

FIG. 14 is a partial schematic plan view of the clamping mechanism ofFIG. 13;

FIG. 15 is a schematic constructional illustration of the clampingmechanism of FIG. 13 as viewed in a direction perpendicular to thepreform transporting direction;

FIG. 16 is a schematic constructional illustration of a molded producttaking out portion of the biaxially stretching blow molding apparatus ofFIG. 1 as viewed from the preform transporting direction; and

FIG. 17 is a schematic constructional plan view of the molded producttaking out portion of FIG. 16.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention will be discussed hereinafter in detail in termsof the preferred embodiment of the present invention with reference tothe accompanying drawings, particularly in terms of a biaxiallystretching blow molding apparatus for molding a polyethyleneterephthalate (PET) bottle, with reference to the accompanying drawings.In the following description, numerous specific details are set forth inorder to provide a thorough understanding of the present invention. Itwill be obvious, however, to those skilled in the art that the presentinvention may be practiced without these specific details. In otherinstance, well-known structures are not shown in detail in order toavoid unnecessarily obscure the present invention.

(Overall Construction and Operation)

FIG. 1A is a schematic plan view of a biaxially stretching blow moldingapparatus, to which the present invention is applied, and FIG. 1B is aschematic side elevation of the biaxially stretching blow moldingapparatus of FIG. 1A. Discussing with reference to these drawings, abiaxially stretching blow molding apparatus 1 has a laterally elongatedbase frame 2. On the upper surface of the base frame 2, a preform supplyportion 3, a preform heating portion 4(1) to 4(5), a stretch-moldingportion 5 of a preform P, and a molded product taking out portion 6 arearranged in sequential order along a preform transporting path.

The shown embodiment of the preform supply portion 3 receives a preformcarrier 7 unloaded a molded product F and transported in an up-side-downcondition. After loading the preform P, the preform carrier 7 isreversed to place in an elected condition. Thereafter, the preformcarrier 7 carrying the preform P is transferred to a pair of guide rails8(1) defining a transporting path at a higher level. Therefore, thepreform supply portion 3 is provided with a first reversing means.

The preform carriers 7 transferred to a pair of guide rails 8(1) aresequentially pushed forward along the guide rails 8(1) and transferredto a transporting path 8(2) passing through heater portions 4(1) to4(5). The transporting path 8(2) has a transporting belt 83 stretchedbetween a drive pulley 81 and a driven pulley 82 and a plurality oftransporting members 84 of preform carriers mounted on the transportingbelt 83 with a given interval and circulated together with thetransporting belt 83. One of straight transporting path portions definedby the transporting belt 83 extends through a heating portion formed byheater portions 4(1) and 4(2). In this portion, a drive mechanism 85 isprovided for rotating the preform P supported on the preform carrier 7transported by the transporting member 84, on its own axis. Similarly,the other straight transporting path portion defined by the transportingbelt 83 extends through a heating portion formed by heater portions 4(3)to 4(5). In this portion, a drive mechanism 86 is provided for rotatingthe preform P supported on the preform carrier 7 transported by thetransporting member 84, on its own axis.

The preform carriers 7 transferred from a pair of guide rails 8(1) tothe transporting members 84 of the transporting path 8(2) aresequentially transported through the heating portions formed by theheater portions 4(1) to 4(5). On the other hand, while passing throughthe heating portions, the preforms P supported by the preform carriers 7are driven by the drive mechanisms 85 and 86 for causing rotation ontheir own axes to be heated the outer peripheral surfaces of respectivepreforms P uniformly.

The preform carriers 7 supporting the preforms P heated through theheater portions 4(1) to 4(5) at a temperature suitable for molding, istransferred to an upper transporting path defined by a pair of guiderails 8(3). The guide rails 8(3) extend through a stretch-moldingportion 5. The stretch-molding portion 5 has left and rightstretch-molding dies 51 and 52 on opposite sides of the preformtransporting path defined by the guide rails 8(3). These stretch-moldingdies 51 and 52 are opened and closed by means of a clamping mechanism53.

On the upstream side of the stretch-molding portion 5 in the preformtransporting direction, a feeding pitch expansion mechanism 9 isarranged. The preform carriers 7 continuously transported toward thestretch-molding portion 5 along the guide rails 8 (3), expands a feedingpitch to be suitable for the molded products F by the feeding pitchexpansion mechanism 9.

Thereafter, with maintaining the expanded feeding pitch, the preforms Psupported by the preform carriers 7 are fed into stretch-moldingposition of the stretch-molding portion 5 by a transfer mechanism 10. Inthe stretch-molding portion 5, the preform P is formed into apredetermined shape of PET bottle (molded product) through a biaxiallystretching blow molding. The preform carrier 7 supporting the PET bottleas the molded product is fed out from the stretch-molding portion 5along the guide rails 8 (3) by the transfer mechanism 10 withmaintaining the expanded feed pitch. Furthermore, by the transfermechanism, the PET bottle as the molded product is transferred to themolded product taking out portion 6 with maintaining the expanded feedpitch.

The molded product taking out portion 6 receives the preform carriersupporting the PET bottle from the guide rails 8(3) and reverses thesame. Furthermore, from the preform carrier 7 placed in up-side-downposition by reversal, the PET bottle is removed. Thereafter, the preformcarrier 7 emptied by removal of the molded product is transferred withmaintaining the up-side-down position to a lower transporting pathdefined by a pair of guide rails 8(4) which are arranged horizontally ata level lower than the level of the guide rails 8(3).

The molded product 7 removed from the preform carrier 7 is transferredto a molded product collecting path 8(6) extending in the oppositedirection of the guide rail 8(4), and is collected in a not showncollecting portion. Such molded product taking out portion 6 is providedwith a second reversing means.

The guide rail 8(4) extends to the preform supply portion 3 through adead space below a pair of stretch-molding dies 51 and 52 of thestretch-molding portion 5, and transfer to the empty preform carrier 7held in up-side-down position to the preformed supply portion 3. In thepreform supply portion 3, after loading the preform on the preformcarrier 7 received in the up-side-down position, the preform carrier 7is reversed into elected position. Thereafter, the preform carrier 7 istransferred to a pair of the guide rails 8(1) defining the transportingpath located at higher level than the guide rails 8(4).

Subsequently, the foregoing procedure is repeated to transfer thepreform by each preform carrier and to repeat biaxially stretching blowmolding.

(Preform, Preform Carrier and Molded Product)

FIGS. 2A to 2C are illustration showing the preform P, the preformcarrier 7 and the molded product F. As shown in FIG. 2A, the preform Pis a primary PET molded product formed into a test-tube like shape withan opening P1 at one end thereof. On the outer peripheral surface in thevicinity of the opening P1, an annular projection P2 is formed.

As shown in FIG. 2B, the preform carrier 7 has a cylindrical main body71. On the outer periphery of the cylindrical main body 71, a flange 72of greater diameter is formed. A portion on one side of the flange 72 isformed as a core portion 73 to be inserted into the opening of thepreform P. On the outer periphery of the portion on the other side ofthe flange 72, an annular flange 74, an annular external gear 75 and anannular plate 76 are mounted in sequential order, and are fixed withpreventing loosing out by a fastening ring 77. The annular flange 74 hasthe largest diameter and serves as a slide portion for slidinghorizontally along guide rails which will be discussed later. On theother hand, the cylindrical main body 71 placed inside of the annularflange 74 is rotatable with respect to the annular flange 74. On thecylindrical main body, the annular external gear 75 is fixed forrotation therewith. Accordingly, when the external gear 75 is rotatinglydriven by a timing belt or the like, the cylindrical main body is drivento rotate about. Therefore, in a condition where the core portion 73formed in the tip end is inserted, the preform P is rotated on its ownaxis.

Next, in FIG. 2C, there is illustrated the molded product F obtained bythe biaxially stretched blow molding in the stretch-molding portion 5.As set forth above, the molded product in the shown embodiment is thePET bottle. On the outer peripheral surface of a next portion F1 isprovided with at least one annular projection. In the shown embodiment,two annular projections F2 and F3 are provided.

(Guide Rail)

FIG. 3A shows guide rails 8(1) and 8(3) for transporting the preformcarrier 7 in elected position and FIG. 3B show the guide rails 8(4)transporting the preform carrier 7 in up-side-down position. On theother hand, FIGS. 3A and 3B also show a height relationship between bothguide rails. Namely, the guide rails 8(4) are lower guide rails locatedat the lowermost height level, and the guide rails 8(1) and 8(3) areupper guide rails.

The guide rails 8(1) and 8(3) have a pair of left and right upper railframes 801 and 802 and a pair of left and right lower rail frames 803and 804. The upper rail frames 801 and 802 are horizontally arranged inparallel relationship with each other with a given spacing therebetween.Similarly, the lower rail frames 803 and 804 are horizontally arrangedin parallel relationship with each other with a given spacingtherebetween. With respectively corresponding upper and lower railframes 801, 803 and 802, 804, guide grooves 805 and 806, into which theannular flange 74 of the preform carrier 7 can be slidably inserted, aredefined. These frame frames 801 to 804 are mounted on a mounting framesor a mounting plates 807 and 808. The mounting plates 807 and 808 aresupported by a base frame 2 via a not shown support frame.

The other guide rails 8(4) have a structure the same as that of theguide rails 8(1) and 8(3) and placed in reversed position. Accordingly,the corresponding parts will be identified by the same referencenumerals as those for the guide rails 8(21) and 8(3), and detaileddiscussion therefore will be neglected for avoiding redundant discussionfor keeping the disclosure simple enough to facilitate clearunderstanding of the present invention. The shown embodiment of theguide rails 8(1), 8(3) and 8(4) are provide structures which cantransport the preform carrier 7 in a condition not permitting loosingout of the preform carrier in vertical direction.

(Preform Supply Portion)

As set forth above, the shown embodiment of the preform supply portion 3receives the empty preform carrier 7 which has been unloaded by removalof the molded product F and transported in the up-side-down positionalong the lower guide rails 8(4). After loading the preform P on thepreform carrier 7, the preform carrier 7 is reversed into the electedposition. Thereafter, the preform carrier 7 is transferred to a pair ofguide rails 8(1) defining the transporting path located at higherposition.

FIG. 4 is a schematic constructional illustration of a preform supplyportion as viewed from a preform transporting direction, FIG. 5 is aschematic constructional illustration showing the preform supply portionas viewed from a direction perpendicular to the preform transportingdirection, FIG. 6 is a schematic constructional plan view of the preformsupply portion and FIG. 7 is a schematic constructional illustration ofthe case where the preform supply portion is viewed in a direction ofarrow 6A of FIG. 6.

Referring to FIGS. 4 to 7, the preform supply portion 3 includes acarrier reversing mechanism 31 for reversing the preform carrier 7 heldin the up-side-down position into the elected position, and a preformloading mechanism 35 supplying the preform P from lower side for thepreform carrier 7 held in the up-side-down position by the carrierreversing mechanism 31.

The carrier reversing mechanism 31 has a pivot shaft 313 extendedhorizontally between a pair of support frame 311 and 312 mounted on thebase frame 2, a rotary cylinder 310 rotating the pivot shaft 313 inforward and reverse directions and a pivot member 314 for rotationintegrally with the pivot shaft 313. The pivot member 314 has a shapesymmetric about the pivot shaft 313 and has carrier holding portions 315and 316 at both ends thereof. In the carrier holding portion 315, a pairof guide grooves 317 and 318 are formed in the same cross-sectionalshape with the guide rail 8(4).

The guide grooves 317 and 318 of the carrier holding portion 315 areplaced at positions respectively matching with positions of the guidegrooves 805 and 806 of the lower guide rails 8(4) as placed at aninitial position of the pivot member 314, namely pivot stop positionshown in the drawing. The other carrier holding portion 316 also has apair of guide grooves 317 and 318 of the same cross-sectional shape asthe guide rail 8(1). These guide grooves 317 and 318 are placed atpositions respectively matching with positions of the guide grooves 805and 806 of the upper guide rails 8(1) as placed at an initial positionof the pivot member 314, namely pivot stop position shown in thedrawing.

On the other hand, in respective of the carrier holding portions 316 and317, preform drop down preventing claws 321 and 322 are arranged. Thepreform drop down preventing claws 321 and 322 are movable in horizontaldirection by drive mechanism, such as electromagnetic solenoids 323 and324. In order to prevent the preform P loaded on the insertion coreportion 73 of the preform carrier held on the carrier holding portions316 and 317, from loosing off the core portion 73, the preform drop downpreventing claws 321 and 322 are designed for engaging with the annularprojecting portion P2 of the preform in the projecting position (one ofthe claws 321 is placed in the projected position in FIG. 4). When theclaws 321 and 322 are returned to the retracted position (the other claw322 is placed in the retracted position in FIG. 4), the claws 321 and322 are released from the annular projection P2 of the preform P.

In the shown embodiment, respective of carrier holding portions 315 and316 have guide grooves of the length which can hold four preformcarriers 7 at once to reverse the preform carrier 7 per four. So as toprevent the preform carrier 7 (7(1) to 7(4)) held by respective carrierholding portions 315 and 316 from moving along the guide groove,positioning plungers 331 and 332 are provided. By projecting fouractuation rods 341 to 344 of the positioning plunger 331, positions ofthe four preform carriers 7 held in the carrier holding portion 315 arefixed. Similarly, by projecting four actuation rods 345 to 348 of thepositioning plunger 331, positions of the four preform carriers 7 heldin the carrier holding portion 316 are fixed.

Next, the preform loading mechanism 35 includes a titled supply groovefor permitting new preforms P to slid down therealong by its own weight,an aligning mechanism 36 receiving the preforms P one by one at thelower end position of the tilted supply groove 351 and aligning fourpreforms in a horizontal direction perpendicular to the tilted supplygroove 351 with a given pitch, and a loading mechanism 37 listing fourpreforms P aligned by the aligning mechanism 36 vertically upward toload the four preforms P held in up-side-down position by one of thecarrier holding portion 315 of the reversing mechanism.

The aligning mechanism 36 has a preform transferring plate 361 formedwith four arc-shaped grooves formed in a given pitch and a directlyacting cylinder 362 for shifting the transferring plate 361 horizontallyin a given pitch. At every time of reception of the preform P in eachgroove of the preform transferring plate 361, the preform transferringplate 361 is moved horizontally at a given feeding pitch.

As shown in FIG. 6, in order perform transfer of the preform P from thetitled supply groove 351 to each groove of the transferring plate 361 atgood timing, a restriction claw 352 for restricting movement of thepreform P in the lower end portion of the tilted supply groove 351, isarranged. The restriction claw 352 is movable between a projectingposition, at which the claw restricts movement of the preform and aretracted position at which the movement of the preform is performedfreely.

The transfer member 361 situated in a condition where the preforms P(1)to P(4) are hanged in respective grooves formed in the given pitch, isthen lifted upwardly by the loading mechanism 37 with maintaining theattitude thereof. The loading mechanism 37 has a lifting cylinder 371.By the lifting cylinder 371, the transferring plate 361 is moved betweenthe initial position shown in FIG. 4 and a lifted position where theinsertion core portions 73 of the preform carriers 7 are completelyinserted into the openings P1 of the preforms P hanged on thetransferring plate 361.

It should be noted that, in the shown embodiment, as can be appreciatedfrom FIG. 4, a support plate 363 is mounted on the base frame 2. On thesupport plate 363, a support plate 365 supporting the lifting cylinder371 via a horizontally extending linear guide 364. On the tip end of anactuation rod of the lifting cylinder 371, the transferring plate 361 isfixedly mounted.

As set forth above, preforms P are loaded per four from the lower sidefor the four preform carriers 7(1) to 7(4) held in the up-side-down(downwardly oriented) position by the carrier holding portion 315 of thereversing mechanism 31. After loading of the preforms P(1) to P(4), thepivoting member 314 is pivoted by the rotary cylinder 310. Then, thecarrier holding portion 315 reaches the position of the carrier holdingposition 316 in FIG. 4. Conversely, the carrier holding portion 316reaches the position of the carrier holding portion 315 in FIG. 4.Thereafter, the plunger 331 and 332 are driven to release respectivepreform carriers 7 held on the carrier holding portions 315 and 316 forfree slide.

Next, as shown in FIG. 1, by driving the push rod 38, the four preformcarriers 7 held in the guide grooves of the carrier holding portion 315are pushed out horizontally from the guide groove of the carrier holdingportion 315. Adjacent position of the carrier holding portion 315, oneends of the upper guides rails 8(1) are located. Therefore, the preformcarriers 7 pushed out from the carrier holding portion 315 aretransferred to the upper guide rails 8(1).

While the preform carriers 7 holding the preforms P are transferred fromthe preform supply portion 3 to the upper guide rails 8(1), thefollowing operation is taken place on the side of the carrier holdingportion 316 on the other side of the reversing mechanism 31. At first,for the carrier holding portion 316, the four preform carriers 7 aretransferred from the lower guide rails 8(4) in upside-down position(downwardly oriented position). For the four preform carriers 7 held onthe carrier holding portion 316, the preforms P are loaded from thelower side, in the manner set forth above.

The reversing mechanism 31 transfers the four preform carriers 7(1) to7(4) holding the preforms P in one of the carrier holding portion to theupper guide rails 8(1), and in turn, receives the four preform carriers7(1) to 7(4) in the other carrier holding portion. After loading thepreforms on the empty preform carriers held on the other carrier holdingportion, the pivoting member 314 is pivoted to place the carrier holdingportion at pivot stop position on the opposite side. With repeating suchoperation, supply of the preform P is performed.

As set forth above, in the shown embodiment of the preform supplyportion 3, the reversing mechanism 31 has carrier holding portions 315and 316 at symmetric position on both ends of the pivoting member 314 toachieve good balance in pivoting motion to realize smooth pivotingoperation. Therefore, pivoting speed can be speeded up. Furthermore,since different operations can be performed simultaneously in thecarrier holding portions 315 and 316 at both ends, work efficiencybecomes higher. Accordingly, it becomes possible to speed-up operationspeed of the biaxially stretching blow molding apparatus 1.

On the other hand, since the carrier holding portions 315 and 316 onboth ends of the pivoting member of the reversing mechanism are placedat different height positions, it becomes possible to transfer thepreform carriers from the lower guide rails 8(4) to the upper guiderails 8(1) located at different height levels with simple mechanism.

(Transporting Path 8(2))

Next, the preform carriers 7 transferred per four to the upper guiderails 8(1) are fed forward along the upper guide rails 8(1). As shown inFIG. 1, the front end portion 821 of the guide rails 821 of the guiderails 8(1) are bent to be placed in the vicinity of a loop form transfermember transporting path. As a result, the preform carrier 7 reachingthe front end portion of the guide rails 8(1) is received within thegroove defined in the transporting member 84 which is circulated alongthe loop form path. Namely, the preform carrier 7 is situated in thecondition where the larger diameter flange 74 rides on the edge of thegroove. Thereafter, the preform carrier 7 supporting the preform P istransported by the transfer member 84.

As set forth above, five heating portions 4(1) to 4(5) are arranged onthe transporting path of the transfer member 84. The preform Ptransported by the transfer member 84 is heated at a temperaturecondition suitable for molding. On the other hand, in the heatingportion, the drive mechanisms 85 and 86 are arranged. Respective drivemechanisms 85 and 86 have timing belts 853 and 863 stretched betweendrive gears 851 and 861, driven gears 852 and 862. Respective timingbelts 853 and 863 are arranged to mesh with the annular external gear 75of each preform carrier 7 transported by the transfer member 84.Accordingly, the preform carrier 7 transported by the transfer member 84is caused rotation of the cylindrical main body 7 rotatably set insideof the larger diameter flange 74 riding on the transfer member 84, onits own axis by the timing belts 853, 863. Namely, the preform P loadedon the insertion core portion 74 formed on the tip end of thecylindrical main body 71, rotates on its own axis.

Thus, the preform P transported across the heating portion 4(1) to 4(5)are transported with rotation on its own axis, respective portion of theouter peripheral surface can be heated uniformly.

On the other hand, by varying the position of the front end portion 821of the guide rail 8(1) to the position between the heating portions 8(1)and 8(2), number of the heating portion to pass the preform, in otherwords, a heating condition, such as heating period, can be easilyvaried.

(Pitch Expansion Mechanism and Transfer Mechanism)

The preform P after heating is expanded the feed pitch by the pitchexpansion mechanism 9 and then fed into the stretch-molding portion 5along the guide rails 8(3) by the transfer mechanism 10. On the otherhand, by the transfer mechanism 10, the molded product F obtained by thestretch-molding portion 5 is transported outside of the stretch-moldingportion 5 along the guide rails 8(3) and transferred to the moldedproduct taking out portion 6.

FIG. 8 is a schematic constructional illustration of the case where apitch expansion mechanism and a transfer mechanism are viewed from apreform transporting direction, FIG. 9 is a schematic plan view of thepitch expansion mechanism before pitch variation as viewed in thedirection of arrow 9A of FIG. 8, and FIG. 10 is a schematic plan view ofthe pitch expansion mechanism after pitch variation. Constructions ofthe pitch expansion mechanism and the transfer mechanism will bediscussed with reference to these drawings.

At first, the pitch expansion mechanism 9 includes a pantographmechanism 90 expandable along the guide rails 8(3), a directly actingcylinder 96 for expanding and contracting the pantograph mechanism 90along the guide rail 8(3), and a directly acting cylinder 976 for movingthe transfer members 91 to 94 back and forth in a directionperpendicular to the direction of the guide rails 8(3).

More particularly, as can be appreciated from FIGS. 8 and 9, on a tipend of a support arm 98 mounted on the base frame 2, movable supportplate 981 which is movable in a direction toward and away from the guiderails 8(3). The movable support plate 981 is movable in a directionperpendicular to the preform transporting direction by the directlyacting cylinder 97 mounted on the support arm 98. On the movable supportplate 981, the main body of the directly acting cylinder 96 is mounted.In conjunction therewith, four transfer members 91 to 94 are supportedvia a linear guides 982. The actuation rod side of the directly actingcylinder 96 is connected to the transfer member 91.

As can be appreciated from FIG. 9, the rear ends of four transfermembers 91 to 94 are rotatably connected with four link articulatedpoints 901 to 904 of the pantograph mechanism 90. On the front ends ofthe transfer members 91 to 94, grooves 91 a to 94 a which can receivecylindrical main bodies 71 of the preform carriers 7 are formed. Itshould be noted that while neglected from illustration, the preformcarriers 7(1) to 7(4) transported along the guide rails 8(3) are stoppedat the position shown in FIG. 9 by means of a stopper.

Operation of the pitch expansion mechanism 9 constructed as set forthabove will be discussed. In the initial state, the transfer members 91to 94 are placed in retracted position retracted from the guide rails8(3). When the preform carrier 8(1) to 7(4) supporting the preforms P(1)to P(4) reach the position opposing to the grooves 91 a to 94 a ofrespective transfer members 91 to 94 placed in the retracted position,respective transporting plates 91 to 94 are driven forward by thedirectly acting cylinder 97 to reach the position shown by solid line inthe drawing to receive the cylindrical main bodies 71 of respectivepreform carriers 7(1) to 7(4).

Next, the pantograph mechanism 90 is expanded by the directly actingcylinder 98. As a result, intervals between the transfer members 91 to94 are connected at respective articulated points are expanded. Thus,pitch of the preform carriers 7(1) to 7(4) held on the transfer members91 to 94, in other words, the pitch of the preforms P1 to P4 supportedthereon, is expanded.

After thus expanding the pitch, the transfer members 91 to 94 arereturned to the retracted position by the directly acting cylinder 97.Next, the transfer member 91 to 94 are narrowed the interval to theinitial interval by the directly acting cylinder 96.

Next, construction of the transfer mechanism 10 for transferring thefour preform carriers 7(1) to 7(4) with maintaining the expended pitchwill be discussed.

The transfer mechanism 10 includes a transfer plate 101, a directlyacting cylinder 102 for moving the transfer plate 101 back and forth ina direction perpendicular to the guide rails 8(3), and a directly actingcylinder 103 for moving the transfer plate 101 back and forth for agiven distance along the guide rails 8(3).

Particularly, as shown in FIGS. 8 and 11, by the base frame 2, themovable support plate 106 is supported via a linear guide 105. Betweenthe base frame 2 and the movable support plate 106, the directly actingcylinder 103 is connected. On the movable support plate 106, thetransfer plate 101 is supported via the linear guide 107. Between themovable support plate 106 and the transfer plate 101, the directlyacting cylinder 103 is connected.

The transfer plate 101 are formed with respective four grooves 111 to114, 121 to 124 and 131 to 134 with an interval corresponding to theexpanded feed pitch, at the ends facing with the guide rails 8(3). Thesethree groups of grooves are formed in equal interval per each group inthe direction along the guide rail.

On the other hand, each groove is a groove which can receive acylindrical portion 74 a of the larger diameter flange 74 of the preformcarrier 7(1) to 7(4) aligned with the expanded feed pitch.

Furthermore, each groove group is placed in such a position that whilethe central group of the grooves 121 to 124 are placed in thestretch-molding portion 5, the group of the grooves 111 to 114 locatedupstream side in the transporting direction are placed for receiving thepreform carriers 7(1) to 7(4) after expansion of the pitch by the pitchexpansion mechanism 9, and the group of the grooves 131 to 134 locateddownstream side in the transporting direction are placed completelytransported out of the stretch-molding portion 5.

The transfer plate 101 constructed as set forth above is moved between aretracted position retracted in the direction perpendicular to the guiderail 8(3) by means of the directly acting cylinder 102 and a frontwardlyshifted position receiving the preform carriers 7 in respective grooves,as shown in FIGS. 8 and 11. On the other hand, the transfer plate 101 ismoved between an initial position shown in FIG. 11 and a feed positionwhere the group of the grooves 111 to 114 reach the position of the nextgroup of the grooves 121 to 124. At this feed position, the group of thegrooves 121 to 124 reaches the position of the group of grooves 131 to134, and the group of the groups 131 to 134 reaches a position of themolded product taking out portion 6 which will be discussed later.

The operation of the transfer mechanism 10 constructed as set forthabove will be discussed. As set forth above, once the feed pitch of thefour preform carriers 7(1) to 7(4) is expanded by the pitch expandingmechanism 9, in advance of placing the our transfer members 91 to 94 ofthe pitch expansion mechanism 9 at the retracted position, the transferplate 101 placed at the retracted position (101A of FIG. 11A) is movedto the frontwardly shifted position (101B) to hold the four preformcarriers 7(1) to 7(4) with the expanded feed pitch. Thereafter, the fourtransfer members 91 to 94 of the pitch expansion mechanism 9 placed intothe retracted position.

Next, the transfer plate 101 is fed from the frontwardly shiftedposition (101B) to the feed position (101C) shown in FIG. 11 by thedirectly acting cylinder 103. As a result, the four preform carriers7(1) to 7(4) held on the group of the grooves 111 to 114 of the transferplate 101 reach the stretch-molding position of the stretch-moldingportion 5.

Here, upon feeding, the four preform carriers 7(1) to 7(4) held by thegroup of the grooves 121 to 124 of the transfer plate 101 are fed outfrom the stretch-molding portion 5. Namely, the molded products F arefed out from the stretch-molding portion 5. On the other hand, the fourpreform carriers 7(1) to 7(3) held by the remaining group of the grooves131 to 134 are fed out to the molded product taking out portion 6.

Next, the transfer plate 101 is retracted from the guide rail 8(3) tothe retracted position (101D) by the directly acting cylinder 102.Thereafter, the transfer plate 101 is returned to the initial position(101A) by the directly acting cylinder 103.

During a period, in which the transfer plate 101 of the transfermechanism 10 is retracted from the feed position (101C) to the retractedposition (101D), and further returns to the initial position (101A), theoperation to widen the feed pitch of the four preform carriers 7(1) to7(4) fed in the narrower feed pitch is performed on the side of thepitch expansion mechanism 9, simultaneously with the foregoingoperation. At a timing where the transfer plate 101 of the transfermechanism 10 is returned to the initial position thereof, the pitchexpansion operation has already be completed.

Thus, in the shown embodiment, the feed pitch expansion mechanism 9 forperforming feed pitch varying operation and the transfer mechanism 10for transporting the preform carriers which is active after expansion ofthe feed pitch are formed in separate constructions. Accordingly, bothare operated simultaneously. As a result, operation speed of thebiaxially stretching blow molding apparatus can be speeded up.

(Stretch-Molding Portion)

In the stretch-molding portion 5, biaxially stretching blow molding isperformed for the preforms P(1) to P(4) supported by the four preformcarriers 7(1) to 7(4) fed into the stretch-molding position as set forthabove by the transfer mechanism 10 along the guide rail 8(3) to form thePET bottle F.

In FIG. 12, there is shown a schematic construction of a stretching rodlifting mechanism and a blowing air supply mechanism in thestretch-molding portion 5 as viewed in the preform transportingdirection. As shown in FIG. 12, immediately below the four preformcarriers 7(1) to 7(4) transported to the stretch-molding position,respective stretching rods 501 are placed in stand-by state as shown inFIG. 12. The stretching rod 501 is supported on an actuation rod 504 ofthe stretching cylinder 503 via a supporting bracket 502. By expandingthe actuation rod 504 of the stretching cylinder 503, the stretching rod501 penetrates into corresponding one of the preforms P(1) to P(4)through the cylindrical main body 71 of one of the preform carriers 7(1)to 7(4) to be lifted up to the position shown by the phantom line withperforming stretching operation.

On the other hand, a cylindrical core 505 for supplying blow air isarranged at the position immediately below the preform carrier withcoaxially surrounding the stretching rod 501. The cylindrical core 505is lifted up with small stroke by a cylinder 506 for the blow core. Atthe lifted position, the cylindrical core 505 is connected to the lowerend opening of the cylindrical main body of the preform carrier. To thecylindrical core 505, a blow air is supplied from a not shown compressedair supply source. Accordingly, when the blow air is supplied in thecondition where the cylindrical core 505 is lifted and connected to thepreform carrier, the blow air is supplied into the preform via thecylindrical core 505 and the preform carrier.

As set forth above, by stretching action by the blow air and thestretching rod, the preform is subject to biaxially stretching moldingin the cavity for forming the PET bottle defined by a pair ofstretch-molding dies 51 and 52 for stretch-molding.

Next, FIG. 13 is a schematic side elevation of the clamping mechanism asviewed from the preform transporting direction, FIG. 14 is a schematicplan view thereof, and FIG. 5 is a schematic side elevation as viewedfrom a direction perpendicular to the preform transporting direction.

Referring to FIGS. 13, 14 and 15, the clamping mechanism 53 has firstand second toggle link mechanisms 54, 55, and swing mechanism 56 forreciprocating operation of the link joint points 541 and 551 insynchronism with that in opposite directions.

The first toggle link mechanism 54 is designed for moving onestretch-molding die 51 along the linear guide 511 supported on the baseframe 2 between open position and close position. The first toggle linkmechanism 54 has a construction, in which two links 542 and 543 areconnected in the direction perpendicular to the preform transportingdirection. The outer end of one link 542 is connected on the side of thebase frame in rotatable fashion, and the inner end of the other link 543is rotatably connected vertically relative to the stretch-molding die51. In the clamped condition, two links 542 and 543 are extendedhorizontally, and in die open position, these link joint point 541 ispushed up and down in elbowed shaped configuration.

The second toggle link mechanism 55 basically has the same constructionas the first toggle link mechanism 54. The other stretch-molding die 52is moved between the open position and the closed position along thelinear guide 521 supported on the base frame 2. The second toggle linkmechanism 55 also has a construction in which two links 552 and 553 areconnected in the direction perpendicular to the preform transportingdirection. The outer end of one link 552 is connected on the side of thebase frame in rotatable fashion, and the inner end of the other link 553is rotatably connected vertically relative to the stretch-molding die51. In the clamped condition, two links 542 and 543 are extendedhorizontally, and in die open position, these link joint point 541 ispushed up and down in elbowed shaped configuration.

The swing mechanism 56 has support plates 561 and 562 mounted on thebase frame 2 in a condition located on both sides of the four stretchmolding positions 5(1) to 5(4) of the stretch molding portion 4 in thepreform transporting direction. On each of the support plates 561 and562, swing plates 563 and 564 are mounted for swing motion in verticaldirection. These swing plates 563 and 564 extend in parallel to thedirection perpendicular to the preform carrier transporting direction.

On both end portions of each swing plate 563 and 564 are connected witheach other by connecting member 565 and 566 extending in the preformtransporting direction. At the center portion of each connecting members565 and 566, connecting pin 567 and 568 extending horizontally in thepreform transporting direction is mounted. To each connecting pin 567and 568, lower end of vertically extending connection shaft 569 and 570is connected rotatably.

On the link joint points 541 and 551 of the first and second toggle linkmechanisms 54 and 55, connecting pins 571 and 572 extending horizontallyin the preform transporting direction are mounted, respectively. Tothese connection pins 571 and 572, upper ends of the connection shafts569 and 570 are connected in rotatable fashion.

Furthermore, a bracket 568 mounted on the central portion of oneconnecting member 566 connecting the swing plates 563 and 564 with eachother, has a projecting portion 568 a projecting outwardly from theconnecting position of the connection shaft 570 relative to the centerof swing. Immediately below the projecting portion 568 a, a die openingand closing cylinder 581 mounted on the base frame 2 is arrangedvertically. A tip end of an actuation rod 582 extending upwardly fromthe cylinder 581 is connected to the projecting portion 568 a inrotatable condition.

Clamping operation of the clamping mechanism 53 constructed as set forthabove will be discussed hereinafter. As can be seen from FIG. 13, in theclamping condition, the first and second toggle link mechanisms 54 and55 are extended horizontally, and the swing plates 563 and 564 are heldin slightly tilted condition ascending toward the stretch-molding die 52with respect to horizontal direction.

Upon opening the die from the clamped condition, the actuation rod 582of the cylinder 581 is retracted to pivot the swing plates 563 and 564to be tilted in the opposite direction as shown by one-dotted line 564Arelative to horizontal direction. By pivoting motion of the swing plates563 and 564, the link connection point 541 of the first toggle linkmechanism 54 connected to one ends thereof are pushed up to be in acondition shown in the phantom line in FIG. 13. In associationtherewith, the stretch-molding die 51 is retracted up to the openposition. In contrast to this, the link connection point 551 of thesecond toggle link mechanism 55 is drawn down to be placed in thecondition shown by phantom line in FIG. 13. In association therewith,the stretch-molding die 52 is retracted to the open position.

Thus, the first and second toggle joint mechanisms 54 and 55 are movedin opposite directions relative to each other with establishingsynchronization. Accordingly, the stretch-molding dies 51 and 52 areretracted relative to each other in the condition where synchronizationis established.

Conversely to the case set forth above, in the clamping operation, theswing plates 563 and 564 are pivoted to the tilted position shown bysolid line of FIG. 13 by pushing out the actuation rod 582 of thecylinder 581. As a result, the links 542, 543 and links 552, 553 of thefirst and second toggle joint mechanisms 54 and 55 are vertically movedin opposite direction in synchronism with each other to be placed inhorizontal condition. As a result, the stretch-molding dies 51 and 52are moved forward in synchronism with each other to establish clampingcondition.

In the shown embodiment of the clamping mechanism 53, utilizing movementat symmetric positions from a pivoting center in the swing plate of thecommon swing mechanism 56, a pair of toggle mechanisms for opening andclosing a pair of stretch-molding dies are moved in mutually oppositedirections with establishing complete synchronization. Accordingly, nolocalized load will never be exerted in respective portions of theclamping mechanism upon opening and closing of the dies to avoidproblems in occurrence of wearing in respective portions and in exertionof impact to respective portions. Therefore, smooth and quick dieopening and closing operation can realized to result in speeding up ofoperation of the biaxially stretching blow molding apparatus 1.

(Molded Product Taking Out Portion)

The molded product taking out portion 6 receives the preform carrier 7supporting the molded product F obtained through the stretch-moldingportion 5 from the upper guide rails 8(3), reverses the preform carrier7 into the up-side-down position with maintaining the molded product,thereafter removes the molded product from the preform carrier 7, andthen transfers the empty preform carrier 7 to the lower guide rails8(4).

FIG. 16 is a schematic constructional illustration of the molded producttaking out portion 6 as viewed from the preform transporting direction,and FIG. 17 is a schematic constructional plan view of the moldedproduct taking out portion of FIG. 16. The construction of the moldedproduct taking output portion 6 will be discussed with reference tothese drawings.

The molded product taking output portion 6 has a carrier reversingmechanism 61 for reversing the preform carrier 7 in elected positioninto up-side-down position, and an unloading mechanism 65 for removingthe molded product F from the preform carrier 7 held in the up-side-downposition as reversed by the carrier reversing mechanism 61.

The carrier reversing mechanism 61 has a pivot shaft 613 horizontallyextending between a pair of support frames 611 and 612 mounted on thebase frame 2, a rotary cylinder 613a for rotating the pivot shaft 613 inforward and reverse directions, and a pivot member 614 rotatingintegrally with the pivot shaft 613. The pivoting member 614 is formedinto a shape symmetric about the pivot shaft 613 and has carrier holdingportions 615 and 616 at both ends thereof.

The carrier holding portion 615 has a pair of guide rails 621 and 622formed with a pair of guide grooves 617 and 618 which have the samecross-section as that of the guide rails 8(3). These guide rails 621 and622 can be lifted relative to a support frame 625 mounted on the pivotmember 614 via linear guides 623 and 634. On the support frame 625, alifting cylinder 626 is mounted. By the lifting cylinder 626, the guiderails 621 and 622 are lifted with a given stroke.

In a condition where the guide rails 621 and 622 are placed in theinitial position, the guide grooves 617 and 618 formed thereon areplaced at positions matching with the guide grooves 805 and 806 on theguide rails 8(3) at the initial position of the pivot member 614, namelypivot stop position as shown in the drawing. The other carrier holdingportion 616 also has guide rails 621 and 622 having a pair of guidegrooves 617 and 618 of the same cross section as those of the guiderails 8(4). The guide grooves 617 and 618 formed on the guide rails 621and 622 of the carrier holding portion 616 are also placed at positionsmatching with the guide grooves 805 and 806 on the guide rails 8(4) atthe initial position of the pivot member 614, namely pivot stop positionas shown in the drawing.

In the shown embodiment, respective carrier holding portions 615 and 616have guide grooves of the length capable of holding four preformcarriers at once for reversing preform carriers 7 per four.

Next, the molded product unloading mechanism 65 has a pair of grippingpieces 651 and 652 which can grip the neck portion F1 of the moldedproduct F loaded on the preform carrier 7 held in the carrier holdingportions 615 and 616, and a pair of guide plates 661 and 662 which canengage with annular projection F2 formed on the outer peripheral surfaceof the neck portion F1 of the molded product.

As can be seen from FIG. 17, a pair of the gripping pieces 651 and 652are formed with curved grooves 651 a and 652 a which can grip a portionbetween two annular projections F2 and F3 of the neck portion F1 of themolded product from opposite sides thereof, on the front faces. In theshown embodiment, the gripping pieces 651 and 652 are respectivelyseparated into four pieces to form four pairs. Respective pair of thegripping pieces can grip respective preform carriers 7(1) to 7(4) fed bythe transfer mechanism 10 from the opposite sides, in place. Opening andclosing of these gripping pieces 651 and 652 is performed by directlyacting cylinders 653 and 654 mounted horizontally on the support frame625 of the pivot member 614.

On the other hand, as can be seen from FIG. 17, inner edges 661 a and662 a of a pair of guide plates 661 and 662 are formed into flatsurfaces extending in parallel to the preform transporting direction.These guide plates 661 and 662 can enter into the lower side of theannular projection F2 of the neck portion F1 of the molded product. Whensuch condition is established, the molding product F can be hanged froma pair of guide plates 661 and 662 by annular projection F2 and, inturn, slidable along the guide plates 661 and 662. Opening and closingof these guide plates 661 and 662 are performed by directly actingcylinders 663 and 664 mounted horizontally on the support frame 625 ofthe pivot member 614.

Operation of the molded product taking out portion 6 constructed as setforth above will be discussed. At first, the four preform carriers 7(1)to 7(4) with supporting the molded products F are fed into the uppercarrier holding portion 615 of the reversing mechanism 61 placed in thestand-by state at the pivot stop condition shown in FIG. 16, along theupper guide rails 8(3), by the transfer plate of the foregoing transfermechanism 10.

Thereafter, a pair of gripping pieces 651 and 652 are advanced from theretracted position shown in FIG. 16 to the advanced position by thedirectly acting cylinders 653 and 654 to grip both sides of the neckportion F1 of the molded product of respective preform carriers 7. Inconjunction therewith, a pair of guide plates 661 and 662 are advancedfrom the retracted position shown in FIG. 16 to the advanced position bythe directly acting cylinders 663 and 664 to be placed in the conditionengaging with the annular side surface of the annular projection F2 ofthe neck portion F1 of the molded product on the preform carrier 7.Thereafter, the transfer plate of the transfer mechanism 10 isretracted.

Next, by pivoting the reversing mechanism 61 over 1800 about the pivotshaft 613, then, the carrier holding portion 615 placed at theright-upper position in FIG. 16 reaches the position of the othercarrier holding portion 616 in FIG. 16. Conversely, the carrier holdingportion 616 reaches the position of the carrier holding portion 615 inFIG. 16. Reversing the carrier holding portion 615 as set forth above,the four preform carries held therein is switched from the electedposition to the up-side-down position.

Here, together with the carrier holding portions 615 and 616, respectivecomponents of the molded product unloading mechanism 65 mounted on thepivoting member 614 are reversed integrally. Accordingly, the moldedproduct F supported by the preform carrier 7 is gripped the neck portionF by the gripping pieces 651 and 652 and is reversed with maintain acondition engaged with a pair of guide plates 661 and 662. Thus, uponreversing operation, the molded product will never loose off the preformcarrier 7.

Next, by means of the lifting cylinder 626, the carrier holding portion615 is lifted up. FIG. 16 shows a condition where the carrier holdingportion 615 is lifted up. When the carrier holding portion 615 is liftedup, four preform carriers 7 are also lifted simultaneously. However, themolded products F supported by respective preform carriers 7 are held inconditions gripped by a pair of gripping pieces 651 and 652.Accordingly, when the preform carriers 7 are lifted up, the insertioncores 73 are released from the molded products F.

Thereafter, a pair of gripping pieces 651 and 652 are retracted torelease the neck portion F1 of the molded product from gripped position.However, since a pair of guide plates 661 and 662 are held in acondition engaged with the lower annular projection F2 of the neckportion F1 of the molded product, the molded product F released from thegripping pieces 651 and 652 are placed in a condition hanged from a pairof guide plates 661 and 662. On the other hand, the molded products Fcan slide along the guide plates 661 and 662. After establishing thiscondition, four molded products F are fed in the direction opposite tothe direction toward the lower guide rails 8(4) by not shown push rod totransfer to the transporting conveyer 665 shown in FIG. 1, by means of anot shown push rod. By the transporting conveyer 665, the moldedproducts F are collected to the predetermined collecting portion (notshown).

In contrast to this, the four preform carriers 7 after removal of themolded product are fed toward the guide rails 8(4) by a push rod 671shown in FIG. 1.

It should be noted that the foregoing discussion has been given mainlyin connection with the operation on the side of one carrier holdingportion 615, the similar removal of the molded products F, feeding outof the molded products and feeding out of the empty preform carriers aretaken place even in the other carrier holding portion 616 at its lowerposition shown in FIG. 16, and infeeding of the preform carriers,gripping of the molded products by the gripping pieces and holding ofthe molded products by the guide plates are performed at its upperposition.

As set forth above, in the shown embodiment of the molded product takingout portion 6, since the reversing mechanism 61 has the carrier holdingportions 615 and 616 at symmetrical positions at opposite ends of thepivoting member 614, it may achieve good balance in pivoting to realizesmooth pivoting operation to result in higher pivoting speed.Furthermore, since different operations can be performed simultaneouslyin the carrier holding portions 615 and 616 at both ends to achieve highwork efficiency. Thus, operation speed of the biaxially stretching blowmolding apparatus 1 becomes higher.

On the other hand, since height difference is provided between thecarrier holding portions 615 and 616 at both ends of the pivoting memberof the reversing mechanism 61,the preform carriers can be transferredfrom the upper guide rails 8(3) to the lower guide rails 8(4) located atdifferent height levels relative to each other, with simply mechanismand quickly. As a result, operation speed of the biaxially stretchingblow molding apparatus 1 becomes higher.

In addition to the construction set forth above, it becomes possible toconstruct the molded product taking out portion 6 to arrange a detectionmechanism for checking good item and no-good item of the molded productsupported on the preform carrier to control opening and closing of apair of gripping pieces and a pair of guide plates on the basis of theresult of checking by the detection mechanism. With employing thisconstruction, if no-good item or rejected product is detected in themolded product taking out portion 6, such no-good item can be separatelycollected for convenience without feeding out on the side of the moldedproduct collecting portion by simultaneously opening the gripping piecesand the guide plates for dropping down.

As set forth above, with the biaxially stretching blow molding apparatusaccording to the present invention, since operation efficiency ofrespective components can be enhanced, the biaxially stretching blowmolding apparatus having high process speed can be realized.

Namely, in the biaxially stretching blow molding apparatus according tothe present invention, the transfer operation of the preform carrierbetween the transporting path at different height level can be performedsimultaneously for both transporting paths utilizing the reversingmeans. Accordingly, transfer operation of the preform carrier betweenthe transporting paths can be done efficiently.

On the other hand, in the preform supply portion of the biaxiallystretching blow molding apparatus according to the present invention,during a period, in which empty preform carrier receiving operation isperformed in one of the preform carrier holding portions, loading ofpreform for the preform carrier and transferring of the preform carriersupporting the preform are performed in the other preform carrierholding portion. Therefore, preform carrier transferring operationbetween the transporting paths and preform supply operation for thepreform carrier can be performed efficiently.

Furthermore, in the molded product taking out portion of the biaxiallystretching blow molding apparatus according to the present invention,during a period, in which preform carriers supporting the moldedproducts are received in one of the preform carrier holding portions,removal of the molded product from the preform carrier and feeding outof the empty preform carriers are performed in the other preform carrierholding portion. Accordingly, transfer of the preform carriers betweenthe transporting paths and taking out operation of the molded productscan be done efficiently.

Next, in the biaxially stretching blow molding apparatus, the feed pitchof the preform carriers is widened upstream of the stretch-moldingportion by the pitch expansion mechanism, and after expansion of thefeed pitch, the preform carriers are fed into the stretch-moldingportion by transfer mechanism separately and independently of eachother. Since the pitch expansion mechanism and the transfer mechanismwhich are operated separately and independently, operation for feedingthe preform carriers carrying the preform into the stretch-moldingportion after expansion of the feed pitch thereof, can be doneefficiently.

On the other hand, in the biaxially stretching blow molding apparatus,the first and second toggle link mechanism movable in oppositedirections and the swing mechanism for moving these first and secondtoggle link mechanism with establishing complete synchronization witheach other are employed as the clamping mechanism for thestretch-molding dies. With such construction, clamping and opening ofdies can be done efficiently. Also, upon these operations, exertion oflocal concentration of the load and impact can be avoided to performclamping operation efficiently and smoothly.

Although the present invention has been illustrated and described withrespect to exemplary embodiment thereof, it should be understood bythose skilled in the art that the foregoing and various other changes,omissions and additions may be made therein and thereto, withoutdeparting from the spirit and scope of the present invention. Therefore,the present invention should not be understood as limited to thespecific embodiment set out above but to include all possibleembodiments which can be embodied within a scope encompassed andequivalents thereof with respect to the feature set out in the appendedclaims.

What is claimed is:
 1. A biaxially stretching blow molding apparatus forbiaxial stretch-molding a preform into a predetermined shape bytransporting a preform carrier supporting said preform along atransporting path extending across a heating portion and astretch-molding portion, comprising: first and second reversing meansfor reversing said preform carrier; first and second transporting pathsforming said transporting path; said first reversing means receivingsaid preform carrier transported in an up-side-down position along saidsecond transporting path, reversing the received preform carrier into anelected position, and transferring said preform carrier thus reversed tosaid first transporting path; and said second reversing means receivingsaid preform carrier transported in the elected position along saidfirst transporting path, reversing the received preform carrier into theup-side-down position, and transferring said preform carrier thusreversed to said second transporting path.
 2. The biaxially stretchingblow molding apparatus as set forth in claim 1, wherein said firsttransporting path is an upper transporting path extending across astretch-molding position of said stretch-molding portion, and saidsecond transporting path is a lower transporting path extending on alower side of said stretch-molding portion.
 3. The biaxially stretchingblow molding apparatus as set forth in claim 2, wherein at least one ofsaid first and second reversing means has a pivoting member pivotingabout a predetermined pivot center and a pair of preform holdingportions formed at symmetric positions of said pivoting member withrespect to said pivot center, one of said preform holding portions beingplaced at a height corresponding to said upper transporting path and theother preform holding portion being placed at a height corresponding tosaid lower transporting path at pivot stop position of said pivotingmember.
 4. The biaxially stretching blow molding apparatus as set forthin claim 3, wherein said preform holding portion formed in said pivotingmeans has a guide groove, into which said preform carrier can beinserted in a lateral direction in a condition not withdrawn in avertical direction, said preform carrier having a slide portion slidingalong said transporting path and being inserted into said guide groove,and a core projecting from said slide portion for inserting into saidpreform.
 5. The biaxially stretching blow molding apparatus as set forthin claim 4, which further comprises a preform supply portion comprising:said first reversing means having said pivoting member and said preformcarrier holding portion; preform inserting means for loading an openingportion of said preform from the lower side to said core of said preformcarrier held in an up-side down position in a guide groove of one ofsaid preform carrier holding portions in said first reversing means; andfeeding out means for feeding out said preform carrier held in theelected position while supporting said preform in said guide groove ofthe other preform carrier holding portion of said first reversing means.6. The biaxially stretching blow molding apparatus as set forth in claim5, wherein said preform supply portion has a drop preventing means forpreventing dropping of said preform loaded on said core of said preformcarrier by said preform inserting means from said core.
 7. The biaxiallystretching blow molding apparatus as set forth in claim 4, wherein saidmolded product taking out portion comprising: said second reversingmeans having said pivoting member and said preform carrier holdingportion; a pair of gripping pieces gripping neck portions of the moldedproducts from both sides loaded on said preform carriers respectivelyheld in said preform carrier holding portion; gripping piece opening andclosing means for moving said gripping pieces between a molded productgripping position and a molded product releasing position; moldingproduct removing means for removing said core of said preform carrierfrom the neck portion of said molded product gripped by said grippingpieces; a pair of guide plates which can be guided in a horizontaldirection while supporting the neck portions of said molded productsloaded on said preform carriers respectively held in said preformcarrier holding portion; and guide plate opening and closing means formoving said guide plates between guiding position of said molded productand a molded product releasing position retracted from said guidingposition.
 8. The biaxially stretching blow molding apparatus as setforth in claim 7, wherein said molded product taking out portioncomprises detecting means for checking good item and no-good item of themolded product supported by said preform carrier; and control means forcontrolling opening and closing said pair of gripping pieces and saidpair of guide plates on the basis of result of checking by saiddetecting means and controlling opening and closing of said pair ofgripping pieces and said pair of guide plates when the preform issupported without being blow molded.